This red shirt, made by Pendleton, is 100% wool.
The shirt was seen on Ebay: https://www.ebay.co.uk/itm/297541253509. Photo credit Help The Next. Seller’s description: ‘Vintage Pendleton Shirt Mens Extra Large Red Plaid Wool Flannel Macpherson Tartan. Condition: Excellent vintage condition with no visible flaws or major wear. All buttons intact. Authentic Pendleton shirt made in the USA. Classic red, navy, green, and yellow plaid pattern in Macpherson tartan. Shell: 100% pure virgin wool for warmth and durability. Lining: 100% nylon for added comfort. Tag size: XL (Mens), See photos for measurements. Button down collar with front button closure. Single chest pocket. Embroidered Pendleton Portland Oregon label and Macpherson Tartan tag inside. Made in the USA. Classic outdoors workwear style from the 1990s’.
Threads of Belonging 